9 of 10 people found the following review helpful.

Stopped Working After 1 Year, Ruined Battery

I mounted a Noco Genius 2D battery maintainer in my truck and it worked as advertized for ~1 year. This morning, after ~1 month of truck stored in garage, battery was totally flat!!! The Error LED was on steady, said to mean "Reverse polarity. Reverse the battery connections. Or battery voltage is too low for charger to detect.". Since the wiring has not changed, and the battery is ~1 year old, the maintainer failed to maintain the voltage and essentially ruined a new battery. Genius it is not; better buying a "dumb" 2A maintainer anywhere else....